This invention relates generally to charging systems for battery operated, cordless tools, appliances and the like and more particularly to such a device used to charge a plurality of portable speaker units at the same time.
Rechargeable appliances have been utilized in the prior art. Such devices typically have a rechargeable battery, such as nickel-metal hydride, lithium or other types known in the art, which are depleted from remote use of the device. The battery may then be recharged and the device used again. Such devices are typically referred to as "cordless" since once the battery is charged, the device may be used without the need of a power cord plugged into a fixed outlet. The convenience that these devices offer the user has contributed to their growing popularity since a user no longer has to rely on the proximity of a power outlet to use the rechargeable device.
Each such rechargeable device typically includes its own recharging adaptor or "rack" which couples between a power outlet and the device and supplies a measured amount of electrical power thereto. Recharging systems are known in the art which recharge a plurality of units simultaneously. One such multistation recharging system is U.S. Pat. No. 5,039,929 to Veistroffer et al. which discloses a battery recharging rack for charging nickel cadmium batteries. The Veistroffer recharging rack includes an elongate rail to which a plurality of battery receptacles are connected. The bottom of the receptacles are connected to positive and negative electrodes which transfer current to a battery received within the receptacle.
Another such multi-unit recharging system is disclosed in U.S. Pat. No. 4,739,242 to McCarty et al. which describes a multistation, modular charging device comprised of units which couple together as needed and are capable of charging multiple rechargeable tools from a single power cord/source. Each charging unit has internal lateral metallic strips which contact the ends of adjacently placed units for electrically connecting multiple units together.
The Veistroffer and McCarty recharging systems are typical of those known in the art whereby they are made up of multiple stations or receptacles each of which will only fit a single one of a certain type of device. For instance, the Veistroffer rack would not allow the rechargeable devices to be placed anywhere along the rack but only in fixed receptacles. Additionally, the rechargeable elements are maintained in contact with the electrodes via gravity only. Thus, the unit must be used upright or else the rechargeable elements will lose contact with the charging electrodes.
Accordingly, a need remains for a recharging system which solves the limitations of the prior art.